Hey y'all, time for two truths and a lie. I'm gonna tell you three things about myself, and you're gonna have to pick out the one that is not true. Ready? Okay. Number one, I have a machine at home that transforms plain water into
carbonated water. Two, I'm really bad at the card game Set, or three, Michael Jackson is my aunt. Is it that obvious? [camera man: Yeeeeah.] God, I'm so bad at game. [intro music] Lying! We do it a lot, and we're a lot better at it
than you'd like to think. Like, I'm not stupid, I could totally have made up a better lie than Michael Jackson is my aunt. But check it out, the fact that I appeared to be terrible at lying was in fact...A lie. In a ten minute conversation with a
stranger, we humans will tell an average of three lies. Researchers who study lying say that the subjects of these lying studies rarely even realize that they're doing it. But why? What purpose does lying actually serve? Well to put human deception into perspective, it's worth pointing out, humans aren't the only
fibbers in nature. My favorite anecdotal example of non-human lying - Koko the gorilla who was taught sign language back in the 1970's once actually blamed her pet kitten for
ripping a sink out of the wall in her room. Bad...bad All Ball. So yeah, lying is nothing new in nature, but why do humans specifically do so
much of it? Well as I've mentioned here before on SciShow, humans are first and foremost social animals. Got really super huge brains, and that's mainly because we need them for all the interacting we're always doing. For humans, successful social interaction is key to success in much of our lives. So it's clear that lying is a great way of keeping elaborate social structures running smoothly while looking out for number
one. For instance, if you can keep your social group happy you're going to reap all kinds of benefits like food, higher social standing, more and better
sexual partners, and you know you don't make friends and influence people going
around saying things like "Actually, that loin cloth does make your butt look big,"
or "Hey, uh, I have been having sex with your
brother while you're out hunting mastodon, so little Glurg over there's... probably your cave nephew." So the ability
to lie, and to detect a lie, became pretty
important to early humans because lying is actually not very easy for a brain to
do, and it actually caused a bit of an evolutionary arms race. So people started to get better and better at lying, and better liars got better stuff, while hopefully remaining in good standing with their communities. By the same token, those who
were better at detecting lies were cheated on by their mates and
screwed over in camel trades a lot less often. So yes, now we've evolved to be good liars and also good at spotting bad liars. But as societies became more sophisticated, folks were like "Okay okay, enough with the lying!", because there are lots of
advantages to living in tight-knit communities and structured
societies, but y'can't really have them, when you don't know for sure
if the kids you're raising are yours, and if the camel you just bought has ever been in an accident or...Whatever. So a society in which bold face
lying goes completely unchecked leads to... total anarchy! So organized societies started putting the hammer down. Religious systems began to drive home the point that God rewards and cares for the truthful and punishes liars. So if you could survive being thrown into the pond tied up with a sack of hammers, God was on your side and you were telling the truth. If not you were obviously lying. Oh, medieval European judicial system, how I love you. Even in our modern times there are laws that prohibit lying and override even our rights to free speech. For instance, you go to jail for lying in a court of law, or for lying about having received a Medal of Honor for service in the armed
forces. Don't do that. Also 'cause you're not... evil. Why would someone do that? So lying. It's not okay. But we're also good at it, and our brains want to do it. We start lying really early, some researchers say as
early as six months old. I mean you've seen a baby fake cry, right? It's very obvious, like they're crying [fake crying noises] then they like, check to see if anybody's coming over to sympathize, and then they're like "Oh, I'm going to keep crying then!" Scientists think that this is the time when babies are actually learning how to be better
liars. By the time the kid's in college they're lying to their mom about once in every five interactions, And actually that seems low to me. I would say five out of five for my college experience. Kids these days. Actually, kids every day. By the time we're adults, we've gotten so very good at lying that we're actually able to do it to ourselves very
effectively. The trick to lying to yourself is in the holding of two pieces of conflicting information in your head at
the same time and paying attention to one, while ignoring the other. People who are good liars can hold a bunch of conflicting information in their heads all at once, and keep track of it all. Take pathological liars - people who habitually and compulsively lie, cheat, and manipulate other people. The thing about pathological liars is that they're super good at self deception. At the moment they're telling it, they
whole-heartedly believe their own lie. Interestingly enough there is an actual difference between the brains
of a normal person and the brain of a pathological liar. That difference is in the very front of the brain in a place called the prefrontal cortex. Most neuro-science studies focus on the on the gray matter of the brain, that's the material that actually processes information. However, nearly half our brains is made up of
what's called white matter, which is composed of connective tissues that carry electrical signals from one group
of neurons to another. So grey matter is where all the processing happens, and
white matter connects the different parts of the brain. In a study at the University of Southern
California, researchers found that pathological liars have about 25 percent more white matter
in their prefrontal cortex than the rest of us, suggesting that pathological liars can make a bunch of connections in their brain really fast. And that lets them keep all the information in order that they need to sustain the lie, also to read the person that they're
lying to, suppress their emotions, and probably believe what they're saying on top of it all. So, why haven't pathological liars taken over the world? I mean they seem to be the next step in human evolution. While pathological liars have a surplus of white matter, they also have around 14 percent less gray matter than other people, and gray matter is we're all the critical thinking happens. So the white matter is all like, "I'm gonna tell Jim I used to be a fighter pilot!" and the grey matter's all "I could tell Jim I used to be a fighter
pilot, but I probably shouldn't because that would jeopardize my relationship
with Tammy." So extreme liars have a really hard time
maintaining relationships and holding down jobs because after a while
everybody realizes that they're full of crap, and they get
dumped or fired. Which is not ideal for the person. It's great for everyone else. But if there are these super liars out there, how do we know if we're being lied to? I mean, lie detectors might be able to pick up signals like change in the liar's voice, or increased heart rate, or sweating, all stuff that we do when we're fibbing outright. But a really good liar might not display any of those symptoms. Well, no matter how good of a liar you are, the fact that you are lying will often leak out, both through your
body language and through your word choices. Let's look at a sample sentence. "Believe me, I was not the one who farted
and evacuated that movie theater!" So do you believe me? Probably not, because I did three things
in that sentence that made you totally certain that I was in fact the
person who made them evacuate the movie theater. To wit: one, I said "believe me". Liars will always say that, or "to be totally honest", or Richard
Nixon's favorite "in all candour". Two, I all of a sudden stopped using contractions. Liars often use more formal language to deny
something that they've actually done. And three, I said "that movie theater"
instead of "the movie theater" - I was trying to distance myself from the whole situation. We think of liars as being fidgety, but we actually tend to freeze our upper bodies when we lie. We make more, not less eye contact. Maybe a little too much to overcompensate for telling a fib. Liars will also do things like shake their
heads while saying yes and smile when they're done telling a
story even if it's a terrible one. All of this stuff, the reading of what we
leak through our words and bodies is actually the future of lie detection - training law enforcement officers to
read potential criminals to catch them in the act of lying. Of course they're always coming up with
new kinds of gadgets all the time too. Eye trackers, MRI brain scanners that are going to replace the old lie-detector tests. Maybe I'll tell my two truths and a
lie on a brain scanner, see how it does. [camera man: Preeetty sure we all know how that's going to turn out.] Yeah, you're right. I'm a terrible liar. Or am I? [maniacal laughter] Thank you for watching this infusion. All of the facts contained within are
not lies, we promise. But if you wanna check there are
citations in the description, of course because we're scientists here. If you have ideas for future episodes of infusions you can leave those in the comments or connect with us on Facebook or
Twitter. Also questions, we'll be happy to answer those as well.
See you next time. [ending music]
